Beware Food Contaminants

Tip #13 Beware Food Contaminants

A large number of scientific studies have addressed the potential for dietary components to influence the risk of developing cancer.

Some compounds find their way into the food supply through agricultural use, animal farming, or food processing, even if their use is not directly intended for human consumption. Examples include growth hormones or antibiotics used in animal farming, small amounts of pesticides and herbicides in plant-based foods, and compounds such as bisphenol A (BPA) or phthalates that enter food from packaging.

Some of these compounds are not known to directly cause cancer, but they may influence cancer risk in other ways – for example, by acting as hormone-like substances in the body.

Unintended contamination of food may also result in exposure to chemicals that are a cause of concern and may be related to cancer risk. Examples include heavy metals such as cadmium or mercury. These metals may enter the food supply if they build up the food chain, such as from fish, or they may enter through contamination or their natural presence in soil or water.


People who eat a regular diet of highly salted food double their risk of stomach cancer, according to a report published today (Tuesday) in the British Journal of Cancer.

A study based on around 40,000 middle-aged Japanese examined dietary, drinking and smoking habits over an 11-year period.

The study shows that the risk of stomach cancer for Japanese men with the lowest salt intake was one in 1000 per year. This doubled to one in 500 among those with the highest salt intake.

For women with a low salt intake the risk was one in 2000, rising to one in 1300 for those whose diet was high in salt.

Gastric or stomach cancer is the second most frequent cause of cancer deaths worldwide with an estimated 776,000 deaths in 1996. It is the fourth most common cancer in the world; in the UK stomach cancer is the sixth most common cancer with 10,000 new cases each year.

Food Additives

Nitrates and Nitrites

In 2010, scientists at the World Health Organization’s International Agency for Research on Cancer declared that ingested nitrites and nitrates are probable human carcinogens.

Nitrites and nitrates are used as preservatives in cured meats such as bacon, salami, sausages and hot dogs Studies have linked nitrites to stomach cancer, cancer of the esophagus, brain and thyroid cancers.

Potassium Bromate

Potassium bromate is used to strengthen bread and cracker dough and help it rise during baking The International Agency for Research on Cancer classifies it as a possible human carcinogen. It causes tumors at multiple sites in animals, is toxic to the kidneys and can cause DNA damage.

Propyl Paraben

Propyl paraben is used as a preservative in foods such as tortillas, muffins and food dyes.

Propyl paraben can alter the expression of genes, including those in breast cancer cells.
Propyl paraben has been reported to accelerate the growth of breast cancer cells.

Butylated Hydroxytoluene (BHT)

BHT is not a listed carcinogen, but some data have shown that it does cause cancer in animals. Rats fed BHT have developed lung and liver tumors.

Propyl gallate

Propyl gallate is used as a preservative in products that contain edible fats, such as sausage and lard. A Toxicology Program study reported an association with tumors in male rats and rare brain tumors in two female rats.

Secret Flavor Ingredients

 “natural flavors” can actually contain synthetic chemicals such as the solvent propylene glycol or the preservative BHA. Flavor extracts and ingredients derived from genetically engineered crops may also be labeled “natural,” BHA is an approved food additive and is also considered “possibly carcinogenic to humans.

Artificial Colors

Caramel colors III and IV may be contaminated with 4-methylimidazole (4-MEI), which caused tumors in a National Toxicology Program study. The European Food Safety Authority has expressed concern about furan contamination, which is also associated with cancer.



Mycotoxins are a group of naturally occurring chemicals produced by certain moulds or fungi and include aflatoxins, ochratoxin A, fumonisins, trichothecenes and zearalenone. Aflatoxins can be found in the milk of animals that are fed contaminated feed, in the form of aflatoxin M1.

Mycotoxins can cause a variety of adverse health effects in humans. Aflatoxins B1 are genotoxic and carcinogenic, and can cause liver cancer in humans.


Dioxins are found throughout the world in the environment and they accumulate in the food chain, mainly in the fatty tissue of animals and pass to human body through food, mainly meat and dairy products, fish and shellfish. Dioxins are highly toxic and can cause cancer.

Acrylamide is a chemical which is found in certain foods that have been cooked and processed at high temperatures. A major concern in humans, given its ability to induce cancers.

Cantaminants in Water

Found in the drinking water, this contaminant can come from hazardous waste sites, industrial spills and discharges from municipal wastewater plants. It is linked to liver, gall bladder and respiratory system cancers.

This notorious poison is a naturally occurring mineral that causes bladder, lung and skin cancers.

The “Erin Brockovich” chemical contaminates drinking water can come from industrial pollution or natural sources. Chromium-6 is linked to stomach cancer.

Disinfection byproducts
These contaminants form when disinfectants such as chlorine interact with plant and animal waste in source water. Disinfection byproducts have been linked to bladder, liver, kidney and intestinal cancers.

Nitrate is a fertilizer chemical that comes from agricultural and urban runoff, as well as discharges from wastewater treatment plants and septic tanks. High levels of nitrate in drinking water have been linked to colon, kidney, ovarian and bladder cancers.

Benefits of Organic Foods

Organic and locally produced foods may have environmental benefits such as using less pesticides or fertilizers. These foods, like others, can be exposed to harmful bacteria during the growing and harvesting process.

What can be done in the kitchen to reduce dietary intake of pesticides?

It is difficult to for a consumer to determine whether vegetables or fruits contain pesticide residues as often they do not have any noticeable smell, taste or visual defect. The following precautions can be taken to reduce dietary exposure to pesticide residue if agricultural products are sold in common market;

  • Thoroughly rinse and scrub fruits and vegetables. Peel them if appropriate.
  • Remove outer leaves of leafy vegetables, such as cauliflower, cabbage.
  • Trim fat from meat, poultry and fish; discard oils and fats in broths and drippings.
  • Throw back the big fish as the little ones have less time to take up and concentrate pesticides and other harmful residues.

These five steps are especially important in preventing foodborne illness :

  • Keep food surfaces clean. Wash all utensils, plates, platters, and cutlery as soon as used.
  • Separate raw food from cooked food.
  • Cook food thoroughly, to the appropriate temperature.
  • Keep food at safe temperatures, both for serving and storage.
  • Use safe water and raw materials

Did you know?

Reusing cooking oil can cause cancer
The problem with reusing oil is that it can create “free radicals” which can cause ailments in the long run. These free radicals can be carcinogenic i.e. can cause cancer and also atherosclerosis which can lead to increase in bad cholesterol levels, blocking the arteries.


Environmental Working Group

World Health Organisation


American Cancer Society

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